/**
 * Copyright (C) 2010-16 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.github.rvesse.airline.annotations.restrictions;

import static java.lang.annotation.ElementType.FIELD;

import java.lang.annotation.Retention;
import java.lang.annotation.Target;

/**
 * An annotation that indicates that an options raw values must match a given
 * regular expression
 */
@Retention(java.lang.annotation.RetentionPolicy.RUNTIME)
@Target({ FIELD })
public @interface Pattern {

    /**
     * The regular expression that must be matched
     * 
     * @return Pattern
     */
    String pattern() default ".*";

    /**
     * The flags for the regular expression
     * 
     * @return Flags
     */
    int flags() default 0;

    /**
     * Provides a description describing the intent of the regular expression,
     * this is often more helpful to end users than an error that their input
     * did not match a regular expression when they may not understand regular
     * expressions
     * 
     * @return Description
     */
    String description() default "";
}
